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Computer Control of Power Systems and Energy Management Systems. Outline. Introduction Conceptual Model of the EMS EMS Functions and SCADA Applications. Time decomposition of the power system operation. Open Distributed system in EMS OOPS. EMS
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Computer Control of Power Systemsand Energy Management Systems
Outline • Introduction • Conceptual Model of the EMS • EMS Functions and SCADA Applications. • Time decomposition of the power system operation. • Open Distributed system in EMS • OOPS
EMS • Enhance the scope of SCADA by providing the power application software to assist the operator in monitoring and controlof the electrical network. • It consists of three important phases: • Gathering Information: Acquisition of real-time data and man machine information. • Decision Making. • Action by Transmitting Control Orders either • - Directly [Centralized Remote Control] • - Indirectly [Decentralized remote control or load • control].
Conceptual Model of EMS Fig 1. Typical EMS Architecture
Real Time Modeling of the system • Network Configuration Analysis • Observability Analysis • State Estimation and Data processing • Network Application Functions
EMS Application and SCADA Functions 1. Real-Time Functions · Topological Analysis · State Estimation · Network Equivalent Calculation · Security Analysis · Generation Dispatch · Voltage and Reactive Optimization 2. Extended Real-Time Functions · Short term Load Forecast · Operator Load Flow · Short Circuit Calculation
The Functions in the EMS can be classified as 1. Primary Analysis (Perform decision making tasks) Programs for Message Switching. Control of Information Display Systems. Recording of Status and events. Information Processing for telecommand and control 2. Secondary Analysis(Operational planning tasks) State Estimation Optimal Power flow Network Security Analysis Load Prediction
Application Functions in Pre-Dispatch, Dispatch and Post-Dispatch modes of an EMS.
Hierarchical Control in EMS • Load frequency Control. • Economic Dispatch. • Power Exchange with Interconnected utilities. • Unit commitment. • Maintenance Scheduling
No Operating State E: Equality Constraint I: Inequality Constraint 1 Normal 2 Alert 3 Emergency 4 In-Extremis 5 Restorative Description of the Operating states
No Operating State From To 1 Preventive Alert Normal 2 Preventive Emergency Through Alert Normal 3 Corrective Emergency Normal Different Types of Control Action
Framework for computer aids for decision making in control centers.
Applications for Energy Management Systems and Energy trading Systems
Open Distributed Systems • Closed System vs. Open System • Closed system software • Restricted to run on a proprietary platform. • Data sharing with other computers extremely difficult. • Open System software • No longer relied on the single vendor to supply all the hardware and software for the EMS • Select the each individual subsystem within the EMS from • different vendors
Impact of Open Systems in EMS • Purchase the hardware and software requirements for the • sufficient capacity only • - Incrementally upgrade the system as and when required. • - This helps in reducing the financial burden on the utilities • to change from the closed system to the open system.
Object Oriented Programming Advantages: 1. Reusability 2. Expandability 3. Portability • Encapsulation (Data Hiding) • 2. Polymorphism (Over Loading) • 3. Inheritance (Specialization) Features of OOPS:
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